INTRODUCTIONTop

The Aegean Sea is an ecologically distinct part of the Mediterranean Sea due to its peculiar hydrographic characteristics. It is an area where the brackish waters of the Black Sea (17‰) merge with the saline waters of the eastern Mediterranean Sea (39‰) (Öztürk et al. 2006Öztürk B., Poutiers J.M., Önen M., et al. 2006. On the Occurrence of Rhomboidella prideaux (Leach, 1815) (Mollusca: Bivalvia: Mytilidae) in the Eastern Mediterranean. The Veliger 48: 215-219.). According to Kocataş and Bilecik (1992)Kocataş A., Bilecik N. 1992. Aegean Sea and its living resources. Water Products Research Institute, Bodrum. 88 pp., ecological features such as temperature, salinity and nutrients fluctuate significantly in the southern Aegean Sea due to the influence of the eastern Mediterranean Sea, and in the northern Aegean Sea due to the influence of the Black Sea. This ecological variation affects the biota in the area.

The genus Alvania Risso, 1826 belongs to the family Rissoidae, which is represented by a high number of genera and species in the northeast Atlantic and Mediterranean Sea (CLEMAM 2016CLEMAM (Check List of European Marine Mollusca). 2016. Accessed 10.10.2016 at www.somali.asso.fr/clemam/index.php). Alvania species are characterized by their typical clathrate sculpture on the teleoconch; ovate-conical shell with axial ribs, and spirals and nodules on their intersections varying according to the species. Alvania are differentiated from other rissoids by having either axial and spiral lines, or cords, on the surface of the teleoconch. The representatives of the genus have a worldwide distribution, with the exception of the Antarctic Ocean and sub-Antarctic regions (Ponder 1985Ponder W.E. 1985. A review of the Genera of the Rissoidae (Mollusca: Mesogastropoda: Rissoacea). Rec. Aust. Mus. 4: 1-221.), and most of the species (about 70%) inhabit the littoral depths, although some of them can be found in deeper areas (Avila et al. 2012Avila S.P., Goud J., de Frias Martins A.M. 2012. Patterns of Diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean Region. Sci. World J. 2012: 164890. ). The Alvania species inhabiting shallow depths feed mostly on periphyton of macrophytes, whereas some bathyal species [e.g. Alvania testae (Aradas and Maggiore, 1844), Alvania jeffreysi (Waller, 1864) and Alvania cimicoides (Forbes, 1844)] feed on the detritus and foraminifers (Fretter and Graham 1978Fretter V., Graham A. 1978. The Prosobranch Molluscs of Britain and Denmark Part. 4 Marine Rissoacea. J. Moll. Stud. 6: 54-241., Ponder 1985Ponder W.E. 1985. A review of the Genera of the Rissoidae (Mollusca: Mesogastropoda: Rissoacea). Rec. Aust. Mus. 4: 1-221.).

Comprehensive revisions of the Rissooidea based on morphological characters have been published by Coan (1964)Coan E. 1964. A Proposed Revision of the Rissoacean Families Rissoidae, Rissoinidae, and Cingulopsidae (Mollusca: Gastropoda). The Veliger 6: 164-171. and Ponder (1985)Ponder W.E. 1985. A review of the Genera of the Rissoidae (Mollusca: Mesogastropoda: Rissoacea). Rec. Aust. Mus. 4: 1-221.. Recently, a phylogenetic analysis of this family testing the diagnostic utility of morphological traits was conducted by Criscione et al. (2016)Criscione F., Ponder W.F., Köhler F., et al. 2016. A molecular phylogeny of Rissoidae (Caenogastropoda: Rissooidea) allows testing the diagnostic utility of morphological traits. Zool. J. Linn. Soc. London 179: 23-40..

The genus Alvania has been the subject of several studies in the Mediterranean Sea (e.g. van Aartsen 1982avan Aartsen J.J.. 1982a. Synoptic tables of Mediterranean and European Conchology (Gen. Alvania). La Conchiglia 14: 20-21., bvan Aartsen J.J. 1982b. Synoptic tables of Mediterranean and European Conchology Genus Alvania: (Subg. Alvinia and Galeodina). La Conchiglia 14: 8-9., cvan Aartsen J.J. 1982c. Sinoptic tables of Mediterranean and European Conchology Gen. Alvania: (Sbg.: Arsenia and Alvaniella). La Conchiglia 14: 4-6., Amati 2014Amati B. 2014. Description of Alvania alicea spec. nov. (Gastropoda, Rissoidae) from the Mediterranean Sea. Iberus 32: 87-95.), where 74 Alvania species are present according to Avila et al. (2012)Avila S.P., Goud J., de Frias Martins A.M. 2012. Patterns of Diversity of the Rissoidae (Mollusca: Gastropoda) in the Atlantic and the Mediterranean Region. Sci. World J. 2012: 164890.. However, few works include taxonomic or ecological information on the representatives of this genus in the eastern Mediterranean (van Aartsen et al. 1989van Aartsen J.J., Barash A., Carrozza F. 1989. Addition to the Knowledge of the Mediterranean Mollusca of Israel and Sinai. Boll. Malacol. 25: 63-76., Cecalupo and Quadri 1996Cecalupo A., Quadri P. 1996. Contributo Alla Conoscenza Malacologica Per Il Nord Dell’Isola Di Cipro (part 3). Boll. Malacol. 31: 95-118.).

Regarding the Turkish coasts, some information on the genus can be found in Forbes (1844)Forbes E. 1844. Report on the Mollusca and Radiata of the Aegean Sea and on their distribution considered as bearing on Geology. Report of the 13th meeting of the British Association Advancement Sc. pp. 5-13., Oberling (1969-1971)Oberling J.J. 1969-1971. On the littoral mollusca of the sea of Marmara. Jahrbuch des Naturhistorischen Museum, Bern, 4: 183-218. and Buzzurro and Greppi (1996)Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., while some species (A. amatii was reported by Oliverio (1986)Oliverio M. 1986. Alvania amatii n, sp. (Gastropoda: Prosobranchia). Notiz. CISMA 7-8: 29-34., A. datchaensis was reported by Amati and Oliverio (1987)Amati B., Oliverio M. 1987. Alvania datchaensis sp. n. (Gastropoda; Prosobranchia). Notiz. CISMA 10: 46-53. and A. bozcaadensis and A. campanii were reported by Tisselli and Giunchi (2013)Tisselli M., Giunchi L. 2013. Due nuove specie di Alvania (Gastropoda: Rissoidae) dal nord-ovest della Turchia. Quad. Studi Nat. Romagna 37: 163-174..

The aim of this study is to contribute to the knowledge of the Alvania species distributed in the Turkish Aegean Sea, including information on their taxonomy, bathymetric distribution, preferred habitats and patterns of distribution. Special attention has been paid to the protoconch due to its importance as a taxonomic character. It can be used to deduce the type of larval development, which has implications for the potential dispersal capacity of larvae in the distribution areas. A multispiral protoconch (typically with more than 2 whorls) suggests planktotrophic larval development, while a paucispiral protoconch (fewer than 2 whorls) is indicative of non-planktotrophic larval development.

MATERIALS AND METHODSTop

The Alvania specimens investigated in this study were collected during various cruises or research projects conducted along the Aegean coast of Turkey between the years 1995 and 2014. The samples were taken from various substrates [sand, mud, mixture of sand and mud, coralligenous, algae (Padina pavonica, Cystoseira amentacea, C. crinita, C. foeniculacea f. schiffneri, C. spinosa, C. elegans, C. compressa, Halopteris scoparia, H. filicina, Ulva linza), phanerogams (Posidonia oceanica, Zostera noltei, Z. marina, Cymodocea nodosa), the sponge Aplysina aerophoba, the scleractinian coral Cladocora caespitosa, the fan shell Pinna nobilis and rocky bottoms] at depths ranging from 0 to 875 m at 39 stations (Fig. 1, Table 1). Benthic samples (10-875 m) were taken by means of a dredge and van Veen Grap, while the shallower water materials (0-10 m) were collected by snorkelling and hand picking. The sampled material was sieved through 0.5 mm mesh and the retained material was fixed in 5% formalin solution. The Alvania specimens were separated from the other benthic materials using a stereomicroscope.

Some shell features of the investigated species, such as total height (H) with standard errors, mean diameter (D) with standard errors, mean height (h) of the last whorl with standard errors and minimum and maximum values for each species [.....] are presented in the following order: H × D – h mm [..... mm; ….. mm].

The protoconch whorls of the investigated species were counted according to Warén (1974)Warén A. 1974. Revision of the Arctic-Atlantic Rissoidae (Gastropoda, Prosobranchia). Zool. Scripta 3: 121-135. and Verduin (1984)Verduin A. 1984. On the taxonomy of some Recent European marine species of the genus Cingula S.I. (Gastropoda: Prosobranchia). Basteria 48: 37-87., while the relevant specimens have been deposited in the museum of the Faculty of Fisheries (ESFM), Ege University (Izmir-Turkey).

RESULTSTop

As a result of the study of the material collected along the Turkish Aegean coast, we identified 537 specimens and 249 shells belonging to 20 species of the genus Alvania. One of them is considered as a new species and is here described and figured for the first time. Table 2 provides a list of the identified Alvania species, the number of living specimens and empty shells obtained of each one, and the stations, habitats and deep range where they were found.

Systematics

Superorder CAENOGASTROPODA Cox, 1960
Superfamily RISSOOIDEA Gray, 1847
Family RISSOIDAE Gray, 1847
Genus Alvania Risso, 1826

Type species: Alvania europea Risso 1826Risso A. 1826. Histoire naturelle des principales productions de l’Europe Méridionale et particulièrement de celles des environs de Nice et des Alpes Maritimes. Paris, Levrault, 4, 439 pp.: 142, pl. 9, Fig. 116 = Alvania cimex (Linnaeus, 1758) (Turbo), by subsequent designation Nevill 1885Nevill G. 1885. Hand list of Mollusca in the Indian Museum, Calcutta. Part II. Gastropoda, Prosobranchia-Neurobranchia (contd.). Government Printer, Calcutta. 306 pp.: 105.

Alvania amatii Oliverio, 1986
(Fig. 2A, B)

Alvania amatii Oliverio, 1986

Mean dimensions (1 specimen and 3 shells): 2.02 (±0.22) × 1.23 (±0.08) – 1.42 (±0.12) mm [1.5 × 1.0 – 1.1 mm; 2.6 × 1.4 – 1.7 mm].

Remarks. Alvania amatii is characterized by its smaller shell dimensions and paucispiral protoconch having 5 spiral threads.

Distribution. The species seems to be an eastern Mediterranean endemic (Oliverio 1986Oliverio M. 1986. Alvania amatii n. sp. (Gastropoda: Prosobranchia). Notiz. CISMA 7-8: 29-34., van Aartsen et al. 1989van Aartsen J.J., Barash A., Carrozza F. 1989. Addition to the Knowledge of the Mediterranean Mollusca of Israel and Sinai. Boll. Malacol. 25: 63-76.). Turkish coasts: Aegean Sea (Oliverio 1986Oliverio M. 1986. Alvania amatii n. sp. (Gastropoda: Prosobranchia). Notiz. CISMA 7-8: 29-34., van Aartsen and Kinzelbach 1990van Aartsen J.J., Kinzelbach R. 1990. Marine Molluscs from the İztuzu Beach near dalyan (Mediterranean coast of Turkey). Zool. Middle East 4: 103-112.) and Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.).

Alvania aspera (Philippi, 1844)
(Fig. 2C, D)

Rissoa aspera Philippi, 1844

Mean dimensions (9 specimens and 1 shell): 1.54 (±0.32) × 1.14 (±0.15) – 1.11 (±0.20) mm [0.7 × 0.6 – 0.6 mm; 3.7 × 2.1 – 2.4 mm].

Remarks. The medium-sized and strong shell, thick axial ribs wider than interspaces on the last whorl and paucispiral protoconch are some of the evident diagnostic features of A. aspera.

Distribution. A. aspera is an eastern Mediterranean endemic (Bogi et al. 1989Bogi C., Cianfanelli S., Talenti E. 1989. Contributo alia conoscenza della malacofauna dell‘isola di Cipro. In Nofroni L. (eds), Atti J Giornata di Studi Malacologici. C.I.S.M.A. Roma (1988), pp. 187-214., Barash and Danin 1992Barash A., Danin Z. 1992. Annotated List of Mediterranean Molluscs of Israel and Sinai. The Israel Academy of Sciences and Humanities, Jerusalem, 405 pp., Zenetos and van Aartsen 1995Zenetos A., van Aartsen J.J. 1995. The deep sea Molluscan Fauna of the S.E. Aegean Sea and its relation to the neighbouring faunas. Boll. Malacol. 30: 253-268.). Turkish coasts: Levantine and Aegean coasts (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140., Öztürk et al. 2008Öztürk B., Önen M., Doğan A. 2008. Türkiye Denizel Mollusca Türleri Tayin Atlası, Ankara, 103T154 nolu Tübitak Projesi, 468 pp.).

Alvania beanii (Hanley in Thorpe, 1844)
(Figs 2E, F, 3D, E, 7K)

Cingula beanie Hanley in Thorpe, 1844

Mean dimensions (39 specimens and 11 shells): 2.83 (±0.12) × 1.62 (±0.05) – 1.86 (±0.07) mm [2.8 × 1.6 – 1.9 mm; 3.9 × 2.1 – 2.4 mm].

Remarks. A. beanii has a multispiral protoconch. It differs from the similar A. hispidula in its greater number of spiral cords on the penultimate and last whorls of the teleoconch.

Distribution. Arctic Ocean (Hudenbick and Warén 1969Hudenbick B., Warén A. 1969. Smasnackor Vid Svenska Vastkusten 1. Slaktet Alvania. Sartryck ur Göteborgs Naturhistoriska Museums Arstryck 55-61.), northeast Atlantic Ocean and Mediterranean Sea (Oliverio et al. 1986Oliverio M. 1986. Alvania amatii n. sp. (Gastropoda: Prosobranchia). Notiz. CISMA 7-8: 29-34., Scaperrotta et al. 2011Scaperrotta M., Bartolini S., Bogi C. 2011. Accrescimenti: Stadi di accrescimento dei Molluschi marini del Mediterraneo. Vol. 3, 184 pp.). Turkish coasts: Aegean Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.), Sea of Marmara (Ostroumoff 1894Ostroumoff A. 1894. K Estestvennoi istorii Bosfora. Prilojenie k LXXIV-my Tomu Zapisok Imper. Akademii Nauk, 5 pp., 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg. 5: 33-92.) and Levantine Sea (Bitlis-Bakır and Öztürk 2016Bitlis Bakır B., Öztürk B. 2016. Rissooidea Species distributed Along the Turkish Levantine Coast. Turk. J. Fish. Aquat. Sc. 16: 443-454.).

Alvania bozcaadensis Tisselli and Giunchi, 2013
(Fig. 2. G, H)

Alvania bozcaadensis Tisselli and Giunchi, 2013

Dimensions of two specimens: 1.8 × 1.2 – 1.3, 1.0 × 0.8 – 0.9 mm.

Remarks. The species can be confused with A. lanciae (Calcara, 1845) and with the juveniles of A. discors, but A. bozcaadensis has no microsculpture on the surface of its protoconch and teleoconch, whereas A. lanciae bears microsculpture on both its protoconch and teleoconch. It differs from A. discors because the protoconch of the later species has a multispiral protoconch, while A. bozcaadensis has a blunt paucispiral apex and fewer axial ribs on the last whorl.

Distribution. Turkish coasts: Levantine and Aegean coasts (Tisselli and Giunchi 2013Tisselli M., Giunchi L. 2013. Due nuove specie di Alvania (Gastropoda: Rissoidae) dal nord-ovest della Turchia. Quad. Studi Nat. Romagna 37: 163-174.).

Alvania cancellata (da Costa, 1778)
(Fig. 2I, J)

Turbo cancellatus da Costa, 1778

Mean dimensions (26 specimens and 5 shells): 3.59 (±0.17) × 2.39 (±0.09) – 2.57 (±0.11) mm [0.9 × 0.8 – 0.7 mm; 4.9 × 3.3 – 3.5 mm].

Remarks. Alvania cancellata is one of the most common and characteristic species of the genus, because of its typical shell structure, large nodule on the base of the columella and multispiral protoconch.

Distribution. Northeast Atlantic Ocean and Mediterranean Sea (Fretter and Graham 1978Fretter V., Graham A. 1978. The Prosobranch Molluscs of Britain and Denmark Part. 4 Marine Rissoacea. J. Moll. Stud. 6: 54-241., Gofas 2007Gofas S. 2007. Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts. J. Nat. Hist. 41: 779-885.). Turkish coasts: Levantine and Aegean coasts (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.), Sea of Marmara (Ostroumoff 1894Ostroumoff A. 1894. K Estestvennoi istorii Bosfora. Prilojenie k LXXIV-my Tomu Zapisok Imper. Akademii Nauk, 5 pp., 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92., Aslan-Cihangir and Ovalis 2013RAslan-Cihangir H., Ovalis P. 2013. Seasonal variations and Structure of the Molluscan Assemblage in the Canakkale Strait (Turkey). Acta Zool. Bulgar 65: 233-250.EF).

Alvania carinata (da Costa, 1778)
(Fig. 2K, L)

Turbo carinatus da Costa, 1778

Dimensions of two specimens: 2.9 × 1.9 – 2.2, 3.4 × 2.4 – 2.6 mm.

Remarks. Alvania carinata can be easily distinguished by the strong spiral sculpture of its teleoconch and paucispiral protoconch.

Distribution. Arctic Ocean (Hudenbick and Warén 1969Hudenbick B., Warén A. 1969. Smasnackor Vid Svenska Vastkusten 1. Slaktet Alvania. Sartryck ur Göteborgs Naturhistoriska Museums Arstryck 55-61.), northeast Atlantic Ocean and Mediterranean Sea (van Aartsen 1982bvan Aartsen J.J. 1982b. Synoptic tables of Mediterranean and European Conchology Genus Alvania: (Subg. Alvinia and Galeodina). La Conchiglia 14: 8-9.). Turkish coasts: Levantine and Aegean coasts (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.).

Alvania cimex (Linnaeus, 1758)
(Fig. 4A, B)

Turbo cimex Linnaeus, 1758

Mean dimensions (31 specimens and 35 shells): 3.44 (±0.15) × 2.37 (±0.06) – 2.58 (±0.09) mm [1.4 × 1.3 – 1.2 mm; 5.7 × 3.4 – 4.0 mm].

Remarks. A. cimex is quite similar to A. mamillata, but they differ in the number of whorls of their protoconchs. The protoconch of Alvania cimex consists of 2-2.3 whorls, compared with about 1.3 whorls in A. mamillata. However, the protoconch figure given by Gianuzzi-Savelli et al. (1997Gianuzzi-Savelli R., Pusateri F., Palmeri A., et al. 1997. Atlas of the Mediterranean Seashells (Caenogastropoda part 1: Discopoda-Heteropoda). Edizioni Evolver, Roma, 258 pp.: 100, fig. 395a) for A. cimex does not seem to belong to this species.

It is stated that the number of protoconch whorls was used as a discriminating feature of the shells, but according to some studies (Oliver et al. 2015Oliver J.D., Calvo M., Guallart J., et al. 2015. Gasterópodos marinos de las islas Chafarinas (Mediterráneo suroccidental). Iberus 33: 97-150., Criscione et al. 2016Criscione F., Ponder W.F., Köhler F., et al. 2016. A molecular phylogeny of Rissoidae (Caenogastropoda: Rissooidea) allows testing the diagnostic utility of morphological traits. Zool. J. Linn. Soc. London 179: 23-40.) the protoconch features do not suffice for correct identification. Oliver et al. (2015)Oliver J.D., Calvo M., Guallart J., et al. 2015. Gasterópodos marinos de las islas Chafarinas (Mediterráneo suroccidental). Iberus 33: 97-150. considered that A. cimex and A. mamillata may be the same species because they have the same distribution, habitats and colour patterns, except for the larval life span. Similarly, Criscione et al. (2016Criscione F., Ponder W.F., Köhler F., et al. 2016. A molecular phylogeny of Rissoidae (Caenogastropoda: Rissooidea) allows testing the diagnostic utility of morphological traits. Zool. J. Linn. Soc. London 179: 23-40.: Fig. 2) stated that the two species shared the same 16S and 28S sequences in the maximum-likelihood phylogram. In this study, we have considered the two species as different taxa, following the current WoRMS (2016)World Register of Marine Species. 2016. WORMS web page. Accessed 10.10.2016 at www.marinespecies.org and CLEMAM (2016)CLEMAM (Check List of European Marine Mollusca). 2016. Accessed 10.10.2016 at www.somali.asso.fr/clemam/index.php databases. Future genetic studies on the larval development of these two species should clarify this aspect.

Distribution. Northeast Atlantic Ocean and Mediterranean Sea (Barash and Danin 1992Barash A., Danin Z. 1992. Annotated List of Mediterranean Molluscs of Israel and Sinai. The Israel Academy of Sciences and Humanities, Jerusalem, 405 pp.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.), Aegean Sea (Kocataş 1978Kocataş A. 1978. İzmir Körfezi Kayalık Sahillerinin Bentik Formları üzerinde Kalitatif ve Kantitatif Araştırmalar. Ege Üniversitesi Fen Fakültesi Monografiler Serisi. 12: 1-93.), Sea of Marmara (Oberling 1969-1971Oberling J.J. 1969-1971. On the littoral mollusca of the sea of Marmara. Jahrbuch des Naturhistorischen Museum, Bern, 4: 183-218.) and Black Sea (Öztürk 1998Öztürk B. 1998. Black Sea biological Diversity, Turkey. Black Sea Environmental Series No 9. United Nations Publish. 144 pp.).

Alvania cimicoides (Forbes, 1844)
(Fig. 4C, D)

Rissoa cimicoides Forbes, 1844

Mean dimensions (3 specimens and 11 shells): 2.32 (±0.21) × 1.46 (±0.10) – 1.57 (±0.12) mm [1.2 × 0.9 – 0.9 mm; 3.5 × 2.0 – 2.3 mm].

Remarks. This species is characterized by its dark brown–coloured and multispiral protoconch. It is distributed mostly at bathyal depths.

Distribution. Arctic Ocean (Hudenbick and Warén 1969Hudenbick B., Warén A. 1969. Smasnackor Vid Svenska Vastkusten 1. Slaktet Alvania. Sartryck ur Göteborgs Naturhistoriska Museums Arstryck 55-61.), eastern Atlantic Ocean and Mediterranean Sea (van Aartsen 1982avan Aartsen J.J.. 1982a. Synoptic tables of Mediterranean and European Conchology (Gen. Alvania). La Conchiglia 14: 20-21., Gofas 2007Gofas S. 2007. Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts. J. Nat. Hist. 41: 779-885.). Turkish coasts: Aegean and Levantine coasts (Forbes 1844Forbes E. 1844. Report on the Mollusca and Radiata of the Aegean Sea and on their distribution considered as bearing on Geology. Report of the 13th meeting of the British Association Advancement Sc. pp. 5-13., Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.), Sea of Marmara (Ostroumoff 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92., Aslan-Cihangir and Ovalis 2013Aslan-Cihangir H., Ovalis P. 2013. Seasonal variations and Structure of the Molluscan Assemblage in the Canakkale Strait (Turkey). Acta Zool. Bulgar 65: 233-250.) and Black Sea (Bacescu et al. 1971Bacescu M.C., Müller G.I., Gomoiu M.T. 1971. Ecologie Marina. Cercetari de Ecologie Bentala in Marea Neagra. Editura Academiei Republicii Socialiste Romania 4, 357 pp.).

Alvania colossophilus Oberling, 1970
(Fig. 4E, F)

Alvania colossophilus Oberling, 1970

Dimension (one shell): 3.7 × 2.2 – 2.3 mm.

Remarks. A. colossophilus may be confused with A. lineata, but the first species differs in the sculpture of its paucispiral protoconch and the stronger and larger size of the shell.

Distribution. The species appears to be an eastern Mediterranean endemic (Bogi et al. 1989Bogi C., Cianfanelli S., Talenti E. 1989. Contributo alia conoscenza della malacofauna dell‘isola di Cipro. In Nofroni L. (eds), Atti J Giornata di Studi Malacologici. C.I.S.M.A. Roma (1988), pp. 187-214., Gianuzzi-Savelli et al. 1997Gianuzzi-Savelli R., Pusateri F., Palmeri A., et al. 1997. Atlas of the Mediterranean Seashells (Caenogastropoda part 1: Discopoda-Heteropoda). Edizioni Evolver, Roma, 258 pp.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.) and Aegean Sea (Okuş et al. 2006Okuş E., Yüksek A., Yokeş M.B., et al. 2006. Coastal and Marine Biodiversity Assessment of Gökova Specially Protected Area Final Report. Environmental Protection Agency for Special Areas, Ministry of Environment and Forestry of Turkey.).

Alvania datchaensis Amati and Oliverio, 1987
(Fig. 4G, H)

Alvania datchaensis Amati and Oliverio, 1987

Mean dimensions (52 specimens and 17 shells): 2.23 (±0.05) × 1.31 (±0.02) – 1.53 (±0.03) mm [1.0 × 0.8 – 0.8 mm; 3.0 × 1.8 – 2.0 mm].

Remarks. It can be distinguished from the other similar Alvania species by the sculpture of its paucispiral protoconch with zigzag spiral lines, and the outer lip without labial varix.

Distribution. It is endemic to the eastern Mediterranean Sea (Cecalupo and Quadri 1996Cecalupo A., Quadri P. 1996. Contributo Alla Conoscenza Malacologica Per Il Nord Dell’Isola Di Cipro (part 3). Boll. Malacol. 31: 95-118., Amati 2012Amati B. 2012. Alvania consociella Monterosato, 1884 junior synonym of Alvania lanciae (Calcara, 1845) (Prosobranchia, Rissoidae). Boll. Malacol. 48: 116-121.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22.) and Aegean Sea (Amati and Oliverio 1987Amati B., Oliverio M. 1987. Alvania datchaensis sp. n. (Gastropoda; Prosobranchia). Notiz. CISMA 10: 46-53., van Aartsen and Kinzelbach 1990van Aartsen J.J., Kinzelbach R. 1990. Marine Molluscs from the İztuzu Beach near dalyan (Mediterranean coast of Turkey). Zool. Middle East 4: 103-112.).

Alvania discors (Allan, 1818)
(Fig. 4I, J)

Turbo discors Allan, 1818

Mean dimensions (218 specimens and 82 shells): 3.12 (±0.09) × 1.97 (±0.03) – 2.13 (±0.05) mm [1.1 × 0.9 – 0.8 mm; 5.3 × 3.0 – 3.4 mm].

Remarks. The species is characterized by its polymorphic shell with a variable number of axial ribs (11-12) and spiral cords (8-9) on the last whorl. The protoconch is multispiral, and its shell may be completely brownish or with white bands.

Distribution. Northeast Atlantic Ocean and Mediterranean Sea (Barash and Danin 1992Barash A., Danin Z. 1992. Annotated List of Mediterranean Molluscs of Israel and Sinai. The Israel Academy of Sciences and Humanities, Jerusalem, 405 pp., Cecalupo and Quadri 1996Cecalupo A., Quadri P. 1996. Contributo Alla Conoscenza Malacologica Per Il Nord Dell’Isola Di Cipro (part 3). Boll. Malacol. 31: 95-118.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.), Aegean Sea (Kocataş 1978Kocataş A. 1978. İzmir Körfezi Kayalık Sahillerinin Bentik Formları üzerinde Kalitatif ve Kantitatif Araştırmalar. Ege Üniversitesi Fen Fakültesi Monografiler Serisi. 12: 1-93.) and Sea of Marmara (Oberling 1969-1971Oberling J.J. 1969-1971. On the littoral mollusca of the sea of Marmara. Jahrbuch des Naturhistorischen Museum, Bern, 4: 183-218.).

Alvania geryonia (Nardo, 1847)
(Figs 4K, L, 7J)

Rissoa geryonia Nardo, 1847

Mean dimensions (26 specimens and 24 shells): 3.29 (±0.10) × 1.91 (±0.04) – 2.27 (±0.06) mm [1.1 × 0.8 – 0.8 mm; 4.5 × 3.3 – 3.5 mm].

Remarks. Alvania geryonia can be misidentified with A. cimex, but the first one has more spirals on the penultimate whorl (5 spiral cords contrary to 3 spiral cords in A. cimex) and smaller granules on the teleoconch. The protoconch is multispiral.

Distribution. Northeast Atlantic Ocean and Mediterranean Sea (van Aartsen 1982avan Aartsen J.J.. 1982a. Synoptic tables of Mediterranean and European Conchology (Gen. Alvania). La Conchiglia 14: 20-21., Gofas et al. 2011Gofas S., Moreno D., Salas C. 2011. Moluscos marinos de Andalucía: I. Introducción general, clase Solenogastres, clase Caudofoveata, clase Polyplacophora y clase Gastropoda (Prosobranchia). Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga, Málaga. 342 pp.). Turkish coasts: Levantine Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.), Aegean Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140., Çınar et al. 2012Çınar M.E., Katağan T., Öztürk B., et al. 2012. Spatio temporal distributions of zoobenthos Mersin Bay (Levantine Sea, eastern Mediterranean) and the importance of alien species in benthic communities. Mar. Biol. Res. 8: 954-968.) and Sea of Marmara (Ostroumoff 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92., Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.).

Alvania hispidula (Monterosato, 1884)
(Fig. 3A-C)

Acinus hispidulus Monterosato, 1884

The shell is solid with 4 convex teleoconch whorls and deep suture. Protoconch is multispiral. On the last whorl, above the aperture, there are 10-14 axial ribs, and 3 spiral cords on the last and penultimate whorls. There is a noteworthy distance between the first spiral cords and the suture. Thickened labrum and light brown coloured shell.

Mean dimensions (2 specimens and 4 shells): 3.42 (±0.09) × 1.72 (±0.10) – 2.19 (±0.06) mm [3.0 × 1.3 – 1.9 mm; 3.7 × 1.9 – 2.3 mm].

Remarks. Alvania hispidula is similar to A. beanii but differs in the number of spiral and axial ribs on the last whorl. Alvania beanii has a smaller shell and 6-7 spiral cords on the last whorl above the aperture, instead of 3 spirals in A. hispidula (4 in the penultimate whorl). The protoconch of A. hispidula (Fig. 3C) and A. beanii (Fig. 3D) are similar, but the protoconch of A. beanii has micro papillae.

Distribution. Atlantic Ocean and Mediterranean Sea (van Aartsen 1982avan Aartsen J.J.. 1982a. Synoptic tables of Mediterranean and European Conchology (Gen. Alvania). La Conchiglia 14: 20-21.). Turkish coasts: Sea of Marmara (Ostroumoff 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92.) and Aegean Sea (this study).

Alvania lactea (Michaud, 1832)
(Fig. 5A, B)

Rissoa lactea Michaud, 1832

Mean dimensions (11 specimens and 6 shells): 3.25 (±0.24) × 2.20 (±0.12) – 2.69 (±0.19) mm [1.2 × 1.1 – 1.1 mm; 4.8 × 3.0 – 3.8 mm].

Remarks. A. lactea differs markedly from the other species of the genus in its shell sculpture and large aperture. The protoconch is paucispiral.

Distribution. Arctic Ocean (Hudenbick and Warén 1969Hudenbick B., Warén A. 1969. Smasnackor Vid Svenska Vastkusten 1. Slaktet Alvania. Sartryck ur Göteborgs Naturhistoriska Museums Arstryck 55-61.), North Atlantic Ocean and Mediterranean Sea (Barash and Danin 1992Barash A., Danin Z. 1992. Annotated List of Mediterranean Molluscs of Israel and Sinai. The Israel Academy of Sciences and Humanities, Jerusalem, 405 pp.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22., Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.), Aegean Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.) and Sea of Marmara (Oberling 1960-1962Oberling J.J. 1960-1962. Une collection de microgastéropodes marins d’Attique. De l’annuaire du musée d’histoire naturelle, Part A. 207-221., 1969-1971Oberling J.J. 1969-1971. On the littoral mollusca of the sea of Marmara. Jahrbuch des Naturhistorischen Museum, Bern, 4: 183-218.).

Alvania lineata Risso, 1826
(Fig. 5C, D)

Alvania costulosa Risso, 1826

Mean dimensions (4 specimens): 3.22 (±0.16) × 2.07 (±0.10) – 2.27 (±0.13) mm [2.8 × 1.9 – 2.0 mm; 3.6 × 2.3 – 2.6 mm].

Remarks. The species differs from the other species of the genus in its large paucispiral protoconch ornamented with spiral threads and in its strong shell, with its axial ribs as wide as the interspaces, with prominent spirals.

Distribution. Mediterranean Sea (Gofas et al. 2011Gofas S., Moreno D., Salas C. 2011. Moluscos marinos de Andalucía: I. Introducción general, clase Solenogastres, clase Caudofoveata, clase Polyplacophora y clase Gastropoda (Prosobranchia). Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga, Málaga. 342 pp.). Turkish coasts: Aegean Sea (Kocataş 1978Kocataş A. 1978. İzmir Körfezi Kayalık Sahillerinin Bentik Formları üzerinde Kalitatif ve Kantitatif Araştırmalar. Ege Üniversitesi Fen Fakültesi Monografiler Serisi. 12: 1-93., Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.), Levantine Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.) and Dardanelles (Aslan-Cihangir and Ovalis 2013Aslan-Cihangir H., Ovalis P. 2013. Seasonal variations and Structure of the Molluscan Assemblage in the Canakkale Strait (Turkey). Acta Zool. Bulgar 65: 233-250.).

Alvania mamillata Risso, 1826
(Figs 5E, F, 6G, 7F-I)

Alvania mamillata Risso, 1826

Mean dimensions (32 specimens and 23 shells): 3.64 (±0.13) × 2.42 (±0.06) – 2.77 (±0.08) mm [1.4 × 1.2 – 1.1 mm; 4.9 × 3.2 – 3.7 mm].

Remarks. (See remarks for A. cimex). The paucispiral protoconch (about 1.3 whorls) and coarse granules on the teleoconch of A. mamillata are noteworthy features of the species.

Distribution. Northeast Atlantic Ocean and Mediterranean Sea (Zenetos and van Aartsen 1995Zenetos A., van Aartsen J.J. 1995. The deep sea Molluscan Fauna of the S.E. Aegean Sea and its relation to the neighbouring faunas. Boll. Malacol. 30: 253-268.). Turkish coasts: Levantine Sea (Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.) and Aegean Sea (van Aartsen and Kinzelbach 1990van Aartsen J.J., Kinzelbach R. 1990. Marine Molluscs from the İztuzu Beach near dalyan (Mediterranean coast of Turkey). Zool. Middle East 4: 103-112.).

Alvania punctura (Montagu, 1803)
(Fig. 5G, H)

Turbo punctura Montagu, 1803

Mean dimensions (42 specimens and 24 shells): 1.78 (±0.05) × 1.06 (±0.02) – 1.21 (±0.02) mm [1.1 × 0.8 – 0.8 mm; 2.5 × 1.3 – 1.5 mm].

Remarks. It is recognizable by its multispiral protoconch and clathrate sculpture of the teleoconch.

Distribution. Arctic Ocean (Hudenbick and Warén 1969Hudenbick B., Warén A. 1969. Smasnackor Vid Svenska Vastkusten 1. Slaktet Alvania. Sartryck ur Göteborgs Naturhistoriska Museums Arstryck 55-61.), Atlantic Ocean and Mediterranean Sea (van Aartsen 1982cvan Aartsen J.J. 1982c. Sinoptic tables of Mediterranean and European Conchology Gen. Alvania: (Sbg.: Arsenia and Alvaniella). La Conchiglia 14: 4-6., Gofas 2007Gofas S. 2007. Rissoidae (Mollusca: Gastropoda) from northeast Atlantic seamounts. J. Nat. Hist. 41: 779-885.). Turkish coasts: Aegean Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.) and Sea of Marmara (Ostroumoff 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92.).

Alvania scabra (Philippi, 1844)
(Fig. 5I, J)

Rissoa scabra Philippi, 1844

Mean dimensions (6 specimens): 1.70 (±0.11) × 1.01 (±0.05) – 1.12 (±0.05) mm [1.4 × 0.8 – 1.0 mm; 2.1 × 1.2 – 1.3 mm].

Remarks. Alvania scabra differs from similar Alvania species in having more spiral cords on the penultimate 4 and last whorls 7-8, respectively. The protoconch is paucispiral.

There are uncertainties about the synonyms of A. scabra. According to the Checklist of European Marine Mollusca (CLEMAM 2016CLEMAM (Check List of European Marine Mollusca). 2016. Accessed 10.10.2016 at www.somali.asso.fr/clemam/index.php), A. oranica was regarded as a synonym of A. scabra. van Aartsen (1982c)van Aartsen J.J. 1982c. Sinoptic tables of Mediterranean and European Conchology Gen. Alvania: (Sbg.: Arsenia and Alvaniella). La Conchiglia 14: 4-6. examined this idea and remarked that the mean difference between A. scabra and A. oranica consisted in having a fourth spiral (always) in the subsutural area of A. oranica, which is rarely found in A. scabra. In addition, Tringali (2001)Tringali L.P. 2001. Marine malacological records (Gastropoda, Prosobranchia, Heterobranchia, Opisthobranchia and Pulmonata) from Torres de Alcala, Mediterranean Marocco, with the description of a new philinid species. Boll. Malacol. 37: 207-222. indicated that the original description and figure of A. oranica given by Pallary (1900Pallary P.P. 1900. Coquilles Marines Du Littoral Du Departement D’oran. J. Conchyl. 212-422.: 322, pl. 7, Fig. 4) was inadequate and still unclear and, due to this fact, A. oranica might be a synonym of A. sculptilis but not of A. scabra. Tringali (2001)Tringali L.P. 2001. Marine malacological records (Gastropoda, Prosobranchia, Heterobranchia, Opisthobranchia and Pulmonata) from Torres de Alcala, Mediterranean Marocco, with the description of a new philinid species. Boll. Malacol. 37: 207-222. also underlined that the figure of A. oranica provided by Gofas (1990Gofas S. 1990. The littoral Rissoidae and Anabathridae of Sao Miguel, Azores. Acoreana 1990: 97-134.: 130, Fig. 58) did not belong to A. oranica. He also stated that the figure of A. scabra in the study by van Aartsen et al. (1984)van Aartsen J.J., Menkhorst H.P.M.G., Gittenberger E. 1984. The marine Mollusca of the Bay of Algeciras, Spain, with general notes on Mitrella, Marginellidae and Turridae. Basteria Supplement 2: 1-135. belongs to A. sculptilis (Monterosato, 1877) instead of A. scabra. In this study, we agree with Tringali’s opinion about the original description of A. oranica, which is insufficient and requires improvement.

Distribution. Mediterranean Sea (van Aartsen 1982cvan Aartsen J.J. 1982c. Sinoptic tables of Mediterranean and European Conchology Gen. Alvania: (Sbg.: Arsenia and Alvaniella). La Conchiglia 14: 4-6., Gofas et al. 2011Gofas S., Moreno D., Salas C. 2011. Moluscos marinos de Andalucía: I. Introducción general, clase Solenogastres, clase Caudofoveata, clase Polyplacophora y clase Gastropoda (Prosobranchia). Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga, Málaga. 342 pp.). Turkish coasts: Levantine Sea (Buzzurro and Greppi 1996Buzzurro G., Greppi E. 1996. The Lessepsian molluscs of Taşucu (South-East Turkey). La Conchiglia 279: 3-22.) and Aegean Sea (van Aartsen and Kinzelbach 1990van Aartsen J.J., Kinzelbach R. 1990. Marine Molluscs from the İztuzu Beach near dalyan (Mediterranean coast of Turkey). Zool. Middle East 4: 103-112.).

Alvania testae (Aradas and Maggiore, 1844)
(Fig. 5K, L)

Rissoa testae Aradas and Maggiore, 1844

Mean dimensions (11 specimens and 2 shells): 2.26 (±0.05) × 1.22 (±0.03) – 1.42 (±0.03) mm [1.9 × 1.0 – 1.2 mm; 2.5 × 1.4 – 1.5 mm].

Remarks. Alvania testae is characterized by its shell shape. The shell is narrow and conical with 5-6 convex teleoconch whorls. Its protoconch is paucispiral. Aperture is roundish and outer lip opisthocline.

Distribution. Atlantic Ocean and Mediterranean Sea (Hoenselaar and Goud 1998Hoenselaar H.J., Goud J. 1998. The Rissoidae of the CANCAP expeditions, I: the genus Alvania Risso, 1826 (Gastropoda Prosobranchia). Basteria 62: 69-115., Gofas et al. 2011Gofas S., Moreno D., Salas C. 2011. Moluscos marinos de Andalucía: I. Introducción general, clase Solenogastres, clase Caudofoveata, clase Polyplacophora y clase Gastropoda (Prosobranchia). Servicio de Publicaciones e Intercambio Científico, Universidad de Málaga, Málaga. 342 pp.). Turkish coasts: Levantine Sea (Bitlis Bakır et al. 2012Bitlis Bakır B., Öztürk B., Doğan A. et al. 2012. Mollusc Fauna of Iskenderun Bay with a Checklist of the Region. Turk. J. Fish. Aquat. Sc. 12: 171-184.), Aegean Sea (Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140., Öztürk et al. 2008Öztürk B., Önen M., Doğan A. 2008. Türkiye Denizel Mollusca Türleri Tayin Atlası, Ankara, 103T154 nolu Tübitak Projesi, 468 pp.) and Sea of Marmara (Ostroumoff 1896Ostroumoff A. 1896. Otchet o dragirovkah i planktonniyh ulovaht ekspeditsia “Selyanika”. Bull. Academie Imperiale des Sciences de St. Petersbourg 5: 33-92., Demir 2003Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.).

Alvania marmarisensis n. sp.
(Figs 6A-F, 7A-E)

Type material and type locality: Holotype (ESFM-GAS/2014-10): Marmaris, 99 m, Aegean Sea; H: 3.3 mm, W: 1.9 mm, BWH: 2.2 mm. Paratypes: 11 specimens (ESFM-GAS/2014-10).

Mean dimensions (20 specimens): 2.96 (±0.08) × 1.84 (±0.03) – 2.07 (±0.04) mm [2.3 × 1.6 – 1.7; 3.5 × 2.1 – 2.4 mm].

Etymology. The name of the species is derived from the name of the area (Marmaris) where the specimens were found.

Description. Shell (holotype): Conical in shape, not very solid, with 4.5 less convex teleoconch whorls. Protoconch (holotype) is paucispiral (~1.25 whorls) and its nucleus diameter is about 0.150 mm. It has irregular spiral lines with rounded micro papillae in the interspaces.

Teleoconch (holotype) has four spirals on the penultimate whorl, 15 axial ribs in the last whorl, 4 spiral cords above the aperture, and 5 spirals on the base. The suture is deep, with a slope between the first and second spiral cords in the penultimate and last whorls. It has small granules at the intersections of the axial ribs, with spiral cords on the teleoconch whorls. There are also fine growth lines on the teleoconch. The aperture is large and ovate. The outer lip is thickened, with 7 internal denticles. It is light-brown coloured, while the apex is often darker. The soft parts and operculum were not examined.

Remarks. Among the species distributed along the Turkish Aegean coast, A. marmarisensis has some similarities with A. beanii, A. geryonia and A. mamillata (Fig. 7). However, it differs from A. beanii and A. geryonia in the number of protoconch whorls and rounded irregular micro papillae . The teleoconch whorls of A. beanii are more convex and have a greater number of axial ribs (24-26) and spiral cords (6-7). Alvania geryonia has a differently shaped teleoconch, with nearly flat whorls, and 5 spirals on the penultimate whorl. The protoconch of A. marmarisensis is also similar to that of A. mamillata (Verduin 1986Verduin A. 1986. Alvania cimex (L.) s. l. (Gastropoda, Prosobranchia), an aggregate species. Basteria 50: 25-32.: 28, Fig. 3; Oliver et al. 2015Oliver J.D., Calvo M., Guallart J., et al. 2015. Gasterópodos marinos de las islas Chafarinas (Mediterráneo suroccidental). Iberus 33: 97-150.: 114, Figs 9, 10, 12, 13), but differs from A. mamillata in being more rounded and having large micro papillae on the protoconch whorls. On the other hand, A. mamillata has a more solid shell and a higher number of axial ribs on the last teleoconch whorl (14-20), and coarser granules at the intersections of the axial ribs with the spirals.

Alvania marmarisensis n. sp. is also morphologically similar to some other Mediterranean species, (i.e. Alvania dalmatica Buzzurro and Prkic, 2007, Alvania dianiensis Oliverio, 1988, Alvania hallgassi Amati and Oliverio, 1985 and Alvania oliverioi Buzzurro, 2003). The new species differs from Alvania dalmatica, A. dianiensis, A. hallgassi and A. oliverioi in the features of its protoconch and teleoconch, geographic distribution and depth ranges (Table 3). Alvania marmarisensis has 1.15-1.25 protoconch whorls, which are ornamented with 5-6 interrupted spiral threads with micro papillae in the interspaces, whereas A. dalmatica has 1.3-1.5 protoconch whorls bearing 6-7 spiral threads of the same thickness, with no papillae in the interspaces (Buzzurro and Prkic 2007Buzzurro G., Prkic J. 2007. A new species of Alvania (Gastropoda: Prosobranchia: Rissoidae) from Croatian coast of Dalmatia. Triton 15: 5-9.: 6, Figs b, c). In addition, the new species has more spiral cords on the penultimate whorl (4 spirals against 3 in A. dalmatica) and on the last whorl (8-9 spirals against 5-9 spirals in A. dalmatica), but the number of denticles inside the outer lip of A. marmarisensis is smaller (6-7) than that of A. dalmatica (7-11). The colour of A. marmarisensis is light brown without coloured stripes as in A. dalmatica.

A. marmarisensis differs from A. hallgassi in having fewer axial ribs on the last whorl (13-17 against 15-40) and no coloured stripes on the whorls. Apart from the differences in the teleoconch, A. marmarisensis has a lower number of protoconch whorls (1.15-1.25 against 1.5 in A. hallgassi) bearing micro papillae in the interspaces between the spirals, which are smooth in A. hallgassi (Amati and Oliverio 1985Amati B., Oliverio M. 1985. Alvania (Alvaniella hallgassi sp. n.) (Gastropoda; Prosobranchia). Notiz. CISMA 6: 28-34.: 34, Figs 1, 2).

Alvania marmarisensis also differs from A. oliverioi in having a higher teleoconch (h=2.3-3.5 mm against h=1.54 mm) and a small number of axial ribs on the last whorl (13-17 against 39-40). The protoconch of A. oliverioi consists of 1.4 whorls with 4-5 weak spirals and regular micro papillae on the whorls (Buzzurro 2003Buzzurro G. 2003. A new species of Alvania from Cyprus (Gastropoda, Prosobranchia, Rissoidae). La Conchiglia 308: 43-46.: 44-45, Figs 2-4) (Table 3).

The protoconch of A. marmarisensis is similar to that of A. dianiensis, except for the protoconch whorls (1.5) (Oliverio 1988Oliverio M. 1988. A new Prosobranch from the Mediterranean Sea, Alvania dianiensis n. sp. (Mollusca; Gastropoda). Bull. Zool. Mus. Univ. Amsterdam 11: 117-120.: 120, Figs 2-7). Alvania marmarisensis is also larger (h=2.3-3.5 mm) and has a higher number of teleoconch whorls (4-4.5) than A. dianiensis (h=2-2.4 mm and 3.2 whorls). Alvania marmarisensis also bears a higher number of spiral cords on the last whorl (8-9 against 6-7), and 4 spirals against 3 spirals above the aperture. There are four spirals on the penultimate whorl in A. marmarisensis against 3 spirals in A. dianiensis. The other difference between the aforementioned two species regards the microsculpture of the teleoconchs; A. marmarisensis has only fine growth lines contrary to fine spiral striae in A. dianiensis (Oliverio 1988Oliverio M. 1988. A new Prosobranch from the Mediterranean Sea, Alvania dianiensis n. sp. (Mollusca; Gastropoda). Bull. Zool. Mus. Univ. Amsterdam 11: 117-120., Romani 2014Romani L. 2014. Alvania dalmatica Buzzurro et Prkic, 2007 (Gastropoda Rissoidae): range extension, shell variability, habitat and relationships with A. hallgassi Amati et Oliverio, 1985. Biodivers. J. 5: 509-514.).

There are also differences in the distribution areas and bathymetric ranges among A. marmarisensis and similar species (Table 3). With the exception of A. marmarisensis and A. dalmatica, all of the mentioned species were collected from infralittoral depths. Alvania marmarisensis was found at a depth of 99 m along the Aegean Sea coast (Marmaris) and Alvania dalmatica was recorded from the coasts of Croatia, Greece and the Adriatic Sea at depths ranging from 40 to 90 m (Buzzurro and Prkic 2007Buzzurro G., Prkic J. 2007. A new species of Alvania (Gastropoda: Prosobranchia: Rissoidae) from Croatian coast of Dalmatia. Triton 15: 5-9., Romani 2014Romani L. 2014. Alvania dalmatica Buzzurro et Prkic, 2007 (Gastropoda Rissoidae): range extension, shell variability, habitat and relationships with A. hallgassi Amati et Oliverio, 1985. Biodivers. J. 5: 509-514.). As regards the species that are similar to A. marmarisensis, A. dianiensis was reported from the Tyrrhenian, Ligurian and Adriatic Seas, from algal beds at depths ranging from 18 to 48 m (Oliverio 1988Oliverio M. 1988. A new Prosobranch from the Mediterranean Sea, Alvania dianiensis n. sp. (Mollusca; Gastropoda). Bull. Zool. Mus. Univ. Amsterdam 11: 117-120., Romani 2014Romani L. 2014. Alvania dalmatica Buzzurro et Prkic, 2007 (Gastropoda Rissoidae): range extension, shell variability, habitat and relationships with A. hallgassi Amati et Oliverio, 1985. Biodivers. J. 5: 509-514.), whereas Alvania hallgassi was described from infralittoral depths of the Ionian Sea (down to 20 m) (Amati and Oliverio 1985Amati B., Oliverio M. 1985. Alvania (Alvaniella hallgassi sp. n.) (Gastropoda; Prosobranchia). Notiz. CISMA 6: 28-34.). This last species was also reported from Sicily, the Adriatic Sea, the Tyrrhenian Sea and the coasts of Cyprus (Oliverio et al. 1986Oliverio M., Amati B., Nofroni I. 1986. Proposta di Adeguamento Sistematico Dei Rissoidaea (sensu Ponder) Del Mar Mediterraneo Parte I: famiglia Rissoidae Gray, 1847 (Gastropoda: Prosobranchia). Notiz. CISMA 7-8: 35-52., Cecalupo and Quadri 1996Cecalupo A., Quadri P. 1996. Contributo Alla Conoscenza Malacologica Per Il Nord Dell’Isola Di Cipro (part 3). Boll. Malacol. 31: 95-118., Romani 2014Romani L. 2014. Alvania dalmatica Buzzurro et Prkic, 2007 (Gastropoda Rissoidae): range extension, shell variability, habitat and relationships with A. hallgassi Amati et Oliverio, 1985. Biodivers. J. 5: 509-514.). Alvania oliverioi was found along the Cypriot coastline at a depth of 4 m (Buzzurro 2003Buzzurro G. 2003. A new species of Alvania from Cyprus (Gastropoda, Prosobranchia, Rissoidae). La Conchiglia 308: 43-46.).

DISCUSSIONTop

Among the analysed benthic material, we sorted 537 living specimens and 249 empty shells belonging to 20 species of the genus Alvania. Of the identified species, Alvania marmarisensis is described as a new species. The new species was only recorded near Marmaris at station 39.1 in muddy material sampled at 99 m depth.

A. mamillata was the commonest species, found at 18 stations in the Aegean Sea, followed by A. discors, found at 15 stations, whereas A. colossophilus was the rarest species with only one specimen found at station 27 (Table 2).

Alvania discors was the most abundant species, with 218 specimens and 82 shells, followed by A. datchaensis (52 specimens and 17 shells). However, A. bozcaadensis, A. carinata and A. colossophilus were only represented by a few specimens or shells (Table 2).

Regarding the bathymetric distribution of the identified species, most of them (14 species) were collected at depths ranging between 0 and 10 m, while 8 species (A. beanii, A. cancellata, A. cimex, A. datchaensis, A. geryonia, A. hispidula, A. mamillata and A. punctura) were found at depths between 10 and 25 m, 6 species (A. beanii, A. cancellata, A. cimex, A. colossophilus, A. geryonia, A. punctura) at depths between 25 and 50 m, and 7 species (A. beanii, A. cancellata, A. geryonia, A. hispidula, A. punctura, A. testae, A. marmarisensis) at depths between 50 and 100 m. Alvania cimicoides and A. testae were distributed at bathyal depths between 93 and 875 m (Table 2).

Bouchet and Warén (1993)Bouchet P., Warén A. 1993. Revision of the Northeast Atlantic bathyal and abyssal Mesogastropoda. Boll. Malacol. 3: 579-840., in their study on the bathyal and abyssal mesogastropod species of the northeastern Atlantic Ocean, dealt with many rissoids, of which 21 species belong to the genus Alvania. Among the Alvania species reported by these authors, A. cimicoides was found at depths between 36 and 4700 m, and A. testae was collected at depths between 36 and 2400 m. In this study, those two species were also found at circalittoral and bathyal depths (93-875 m; sta. 2, sta. 6, sta. 7, sta. 8 and sta. 28).

Bitlis Bakır and Öztürk (2016)Bitlis Bakır B., Öztürk B. 2016. Rissooidea Species distributed Along the Turkish Levantine Coast. Turk. J. Fish. Aquat. Sc. 16: 443-454 investigated Rissooidea species distributed along the Turkish Levantine coast and reported 15 Alvania species, which have also been examined within the context of this study. A. beanii (60-1302 m) and A. testae (100-200 m), which were sampled at circalittoral and bathyal depths in the mentioned study, were encountered in our study at depths between 23 and 100 m and 93 and 875 m, respectively.

Regarding the habitats where these species were found, seagrass meadows (Posidonia oceanica, Zostera noltei, Z. marina, and Cymodocea nodosa) were the most diverse, housing 14 species, followed by algal beds (Padina pavonica, Cystoseira amentacea, C. crinita, C. foeniculacea f. schiffneri, C. spinosa, C. elegans, C. compressa, Halopteris scoparia, H. filicina, Ulva linza) and hard substrates (rock, Cladocora caespitosa, Aplysina aerophoba, Pinna nobilis), both with 11 species, and soft substrates (sand, mud, mixture of sand and mud, and coralligens) with 10 species (Table 2).

The preferred habitats of Alvania species found during this study are in agreement with those given by Antoniadou et al. (2005)Antoniadou C., Koutsoubas D., Chintiroglou C. 2005. Mollusca fauna from infralittoral hard substrate assemblages in the North Aegean Sea. Belgian J. Zool. 135: 119-126, Albano and Sabelli (2012)Albano P.G., Sabelli B. 2012. The molluscan assemblages inhabiting the leaves and rhizomes of a deep water Posidonia oceanica settlement in the central Tyrrhenian Sea. Sci. Mar. 76: 721-732., Pitacco et al. (2014)Pitacco V., Orlando-Bonaca M., Mavric B. et al. 2014. Mollusc fauna associated with the Cystoseira algal associations in the Gulf of Trieste (Northern Adriatic Sea). Medit. Mar. Sci. 15: 225-238.. In the North Aegean Sea, A. aspera, A. cimex, and A. mamillata were reported from habitats of photophilic algae, and A. discors was found in soft sediments and in P. oceanica (Antoniadou et al. 2005Antoniadou C., Koutsoubas D., Chintiroglou C. 2005. Mollusca fauna from infralittoral hard substrate assemblages in the North Aegean Sea. Belgian J. Zool. 135: 119-126.). In this study, A. aspera was encountered in algal beds, while A. cimex, A. discors and A. mamillata were found in photophilic algae, soft sediments and P. oceanica. Albano and Sabelli (2012)Albano P.G., Sabelli B. 2012. The molluscan assemblages inhabiting the leaves and rhizomes of a deep water Posidonia oceanica settlement in the central Tyrrhenian Sea. Sci. Mar. 76: 721-732. examined the molluscan fauna inhabiting the leaves and rhizomes of P. oceanica distributed in the central Tyrrhenian Sea and reported A. cancellata, A. hispidula and A. settepassii. Likewise, A. cancellata and A. hispidula were encountered in P. oceanica meadows along the Turkish Aegean coast. Pitacco et al. (2014)Pitacco V., Orlando-Bonaca M., Mavric B. et al. 2014. Mollusc fauna associated with the Cystoseira algal associations in the Gulf of Trieste (Northern Adriatic Sea). Medit. Mar. Sci. 15: 225-238. stated that A. cimex, A. discors and A. lineata preferred Cystoseira beds in the Gulf of Trieste. In this study, those Alvania species were also found in Cystoseira communities (C. amantacea, C. crinita, C. compressa, C. spinosa, C. foeniculacea f. schiffneri). Poursanidis and Koutsoubas (2015)Poursanidis D., Koutsoubas D. 2015. A computerized database (CorMol) on the molluscan fauna from the Mediterranean reef ecosystems: Part I, the coralligenous formations. Quat. Int. 390: 29-43. reported 15 Alvania species inhabiting the coralligenous habitats of the Mediterranean Sea, of which only A. beanii, A. cancellata and A. geryonia were found in this study. In a study carried out in the Mediterranean Sea by Poursanidis et al. (2016)Poursanidis D., Koutsoubas D., Arvanitidis C., et al. 2016. ReefMedMol: Mollusca from the infralittoral rocky shores - the biocoenosis of photophilic algae - in the Mediterranean Sea. Biodivers. Data J. 4: e7516., 21 Alvania species were reported from the infralittoral rocky shores and photophilic algae, of which A. cimex, A. discors, A. geryonia, A. lactea, A. lineata, A. mamillata, A. scabra were also found during our study, in rocky and algal biotopes. Along the Levantine coast of Turkey, A. mamillata, A. geryonia, A. discors and A. datchaensis were found to be dominant in sandy biotopes, seagrass meadows and red algae (Bitlis Bakır and Öztürk 2016Bitlis Bakır B., Öztürk B. 2016. Rissooidea Species distributed Along the Turkish Levantine Coast. Turk. J. Fish. Aquat. Sc. 16: 443-454). As regards the species of this study, A. mamillata and A. geryonia were found in soft sediments, phanerogams, hard substrate and brown algae, whereas A. discors and A. datchaensis were encountered in phanerogam meadows, hard substrates and brown algae.

It is assumed that the difference in the number of protoconch whorls depends on differences in larval development (planktotrophic vs non-planktotrophic), which may affect the distribution range of the species. Therefore, eight Alvania species (A. beanii, A. cancellata, A. cimex, A. cimicoides, A. discors, A. geryonia, A. hispidula and A. punctura) with multispiral protoconch examined during this study have a wide distribution in the Atlantic Ocean and the Mediterranean Sea. However, A. amatii, A. lineata, A. scabra, A. aspera, A. bozcaadensis, A. colossophilus and A. datchaensis have a paucispiral protoconch and are endemic to the Mediterranean Sea, and some of them have a restricted distribution. However, contrary to the above, some Alvania species (A. carinata, A. lactea) with paucispiral protoconch are widely distributed in the Atlantic and Arctic Oceans, and in the Mediterranean. Therefore, it may be concluded that the geographical distribution of a species cannot be explained on the basis of protoconch type only, which in fact may also depend on other ecological or historical features.

The shell dimension data obtained from the study were compared with those of Alvania species distributed along the Levantine coast of Turkey (Bitlis Bakır and Öztürk 2016Bitlis Bakır B., Öztürk B. 2016. Rissooidea Species distributed Along the Turkish Levantine Coast. Turk. J. Fish. Aquat. Sc. 16: 443-454), and some species (A. aspera, A. bozcaadensis, A. cimex, A. lactea and A. testae) from the Turkish Levantine coast were found to be taller than those of our study. However, the shells of A. discors, A. mamillata and A. scabra from the Levantine Sea were smaller than those originating from the Turkish Aegean coast.

According to the checklist published by Öztürk et al. (2014)Öztürk B., Doğan A., Bitlis-Bakır B., et al. 2014. Marine Molluscs of the Turkish Coasts: An Updated Checklist. Turk. J. Zool. 38: 1-48., 27 Alvania species were reported along the Turkish coasts, of which 24 are known to be distributed along the Aegean coast of Turkey; six of these species [A. campanii Tisselli and Giunchi, 2013, A. dorbignyi (Audouin, 1826), A. lanciae (Calcara, 1845), A. rudis (Philippi, 1844), A. settepassii Amati and Nofroni, 1985 and A. zetlandica (Montagu, 1816)] reported from the Turkish Aegean coast in earlier studies were not encountered in this study. To date, A. lanciae, A. rudis and A. zetlandica have only been reported from the Aegean coast of Turkey by Demir (2003)Demir M. 2003. Shells of Mollusca Collected from the Seas of Turkey. Turk. J. Zool. 27: 101-140.. Yokeş and Demir (2013)Yokeş M.B., Demir V. 2013. Ayvalık Adaları Tabiat Parkı Denizel Biyolojik Çeşitlilik Çalışması. Teknik rapor Serisi 20: 104. reported A. settepassii along the Turkish coasts for the first time (Gökova Bay), but this species has not been recorded again from the Turkish coasts.

Although with some doubts, A. dorbignyi is the only Alvania species considered as alien. Its distribution in the Mediterranean Sea is limited to the eastern basin only: Cyprus (Bogi et al. 1989Bogi C., Cianfanelli S., Talenti E. 1989. Contributo alia conoscenza della malacofauna dell‘isola di Cipro. In Nofroni L. (eds), Atti J Giornata di Studi Malacologici. C.I.S.M.A. Roma (1988), pp. 187-214.), Israel (Barash and Danin 1992Barash A., Danin Z. 1992. Annotated List of Mediterranean Molluscs of Israel and Sinai. The Israel Academy of Sciences and Humanities, Jerusalem, 405 pp., Delongueville and Scaillet 2007Delongueville C., Scaillet R. 2007. Les espéces invasives de mollusques en Mediterranée. Novapex 8: 62.) and Tunisia (Campani 2009Campani E. 2009. An odd finding of Alvania dorbignyi (Gastropoda: Rissoidae). Mar. Biodiver. Rec. 2: 1-2.). The origin of A. dorbignyi is still unclear. Nordsieck (1972)Nordsieck F. 1972. Die europaischen Meeresschnecken (Opisthobranchia mit Pyramidellidae; Rissoacea), 327 pp. suggested that this species originates from the Red Sea, but Mienis (1985)Mienis H.K. 1985. Is Alvania dorbignyi (Audouin, 1826) A Lessepsian Migrant? Levantina 59: 652-654. did not share this opinion, arguing that the species may have Indo-Pacific origin or is an anti-Lessepsian migrant. We found no specimens of the species, but it is clear that its distribution and origin need to be investigated in detail.

As a result of this study, the number of Alvania species distributed along the Aegean coast of Turkey has increased to 26 species with the addition of A. hispidula and A. marmarisensis n. sp. The Aegean Sea has fairly high biological diversity, due to its hydrographic characters and geomorphologic structures. Regarding the molluscan fauna, the Aegean coast of Turkey is the richest coast of Turkey (Öztürk et al. 2014Öztürk B., Doğan A., Bitlis-Bakır B., et al. 2014. Marine Molluscs of the Turkish Coasts: An Updated Checklist. Turk. J. Zool. 38: 1-48.).

ACKNOWLEDGEMENTSTop

The authors are much indebted to Bruno Amati (Roma, Italy) and Morena Giunchi (San Zaccaria (RA), Italy) for their advice and confirmation of some Alvania species, and to the editor and two anonymous referees for their constructive comments.

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